The fresh secretion from animals used for the nourishment of young ones is:

Some hormones prevent the secretion of milk by the mammary glands until the birth of the young ones,even though the glands are fully prepared to do so. These hormones are:

Which mechanism is responsible for parturition?

$A$: Colostrum is a very efficient means of transferring immunity to a newborn.
$R$: $IgM$ from mother's milk protects the baby from the respiratory infection usually affecting in young age.

Which hormone inhibits the menstrual cycle in females during the period of lactation?

Which gland in the female undergoes differentiation during pregnancy and lactation?